The present invention generally relates to transmission control in data terminal equipment and, more particularly, to transmission control in a data terminal equipment unit connected to the ISDN and equipped with a multi-link communications function for carrying out data communication using a plurality of ISDN information channels.
Several types of data terminal equipment using the ISDN as a transmission line, such as group 4 facsimile machines, are proposed and actually used which equipment are equipped with a multi-link communication function for carrying out data communication using a plurality of ISDN information channels.
With the use of the multi-link communications function in performing data communication (for example, when sending color image of natural scenery), a long period of time otherwise required for the transmission is substantially reduced, and the communications cost is substantially reduced.
A problem with the conventional equipment is that, since the data communication therein is started after a desired number of information channels have been established, certain period of time is wasted in a communication session, thereby failing to exhibit an expected performance.